Change and Refugia: Potential Biome Shifts in a Changing Climate
Biome composition is strongly influenced by climate, through direct effects on individual
species (based on metabolic requirements and heat and cold tolerance) as well as via the
limiting and defining effects of season length, water availability, and snow cover. Thus,
climate change will eventually shift the species composition and ultimately the biomes of
Alaska and western Canada. A collaborative group including the US Fish and Wildlife
Service (USFWS), The Nature Conservancy (TNC), the UAF EWHALE lab, and the UA
Scenarios Network for Alaska Planning (SNAP) has examined the possible extent of
these shifts. We based our analyses on SNAP monthly temperature projections at 2km
resolution, which are created using outputs from five selected Global Circulation Models,
downscaled using the PRISM model. In the first iteration of the project, completed in
2010, we linked six Alaskan biomes and six Canadian biomes -- defined based on the
literature -- to their current June and December temperature and precipitation, and then
projected potential shifts as a function of climate change. Our results showed broad-scale
potential change, particularly in northern and western Alaska. In an effort to refine these
results, with support from the Arctic Landscape Conservation Cooperative, we embarked
upon a second iteration in which we used all twelve months of data, and defined biomes
more organically, via data clustering. Analysis of areas of greatest change and least
change will allow land managers to assess how to direct conservation efforts and where
to expect either threshold change or refugia.